Ignition Characteristics of HAN Liquid for Gas-Hybrid Rockets

Gas-hybrid rockets get thrust by combusting the mixture gas of a fuel-rich hot gas and an atomized liquid oxidizer. Many kinds of liquid oxidizers are used for the gas-hybrid rockets. These are very difficult to handle because they have toxins or is not liquid at ordinary temperatures and pressures. In this study, we focused on hydroxylammonium nitrate (HAN) liquid as the liquid oxidizer for the gas-hybrid rockets. HAN liquid is easy to handle because it has very few toxins and is a stable substance at ordinary temperatures and pressures. It is important to observe single droplet because atomized HAN liquid oxidizer consist of many droplets. And it is considered that HAN concentration affect ignition characteristics of the HAN droplets. Therefore, we investigated relationships between HAN concentration and ignition characteristics of the HAN droplets by obtaining the decomposition delay time of the HAN droplets (τde).